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A library that parses and evaluates mathematical formulas in textual format.
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/*
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*/
package types;
import core.NodeRecognizedInfo;
import core.VariablesManager;
import java.util.ArrayList;
import java.util.List;
import core.Token;
import core.Utils;
import exceptions.EvaluationException;
import exceptions.InvalidFormatException;
/**
*
* @author haitham
*/
public class MaxNode extends AbstractMultiOpNode {
private VariablesManager varManager;
public MaxNode(
AbstractNode parent,
List allTokens,
VariablesManager varManager) {
super(parent, allTokens);
this.varManager = varManager;
}
@Override
public double evaluate() throws EvaluationException {
double max = getChild(0).evaluate();
for (int i = 1; i < getChildrenCount(); i++) {
double childValue = getChild(i).evaluate();
if (childValue > max) {
max = childValue;
}
}
return max;
}
public static NodeRecognizedInfo findLastOccurence(
List targetTokens,
List allTtokens,
AbstractNode parent,
VariablesManager vm) throws InvalidFormatException {
// Loop over all tokens from the end to the beginning
for (int i = targetTokens.size() - 2; i >= 0; i--) {
// Check if the token is enclosed in brackets, braces or parentheses
if (!Utils.surrounded(targetTokens.get(i), targetTokens)) {
// Try to match the operator
if (targetTokens.get(i).getString().equalsIgnoreCase("max")) {
// the keyword "max" must be followed by "("
if (targetTokens.get(i + 1).getString().equals("(")) {
// The following commented block used to prevent this
// operator from accept other nested operators that have
// parentheses in them e.g. tan(). So, we replaced it by
// the following block (borrowed from TrigTanNode)
// // Look for ")"
// int last = i;
// while (last < targetTokens.size()
// && !targetTokens.get(last).getString().equals(")")) {
// last++;
// }
// Look for ")" ... This is the block borrowed from TrigTanNode
int j = i;
int last = -1;
while (j < targetTokens.size()) {
if (targetTokens.get(j).getString().equals(")")) {
last = j;
}
j++;
}
// Now (last) points to the location of the ")" token
if (last == targetTokens.size()) {
// This means that the closing ")" is missing
throw new InvalidFormatException(
targetTokens.get(i),
allTtokens,
"Max operator closing bracket ')' is missing.");
} else {
// Get all the arguments between "(" and ")"
// which should be separated by comma tokens ","
// unless only one expression is provided inside the
// max operator (which although useless is permitted).
// First, collect commas indices
List commaIndices = new ArrayList<>();
for (int k = i + 2; k < last; k++) {
if (
// The first condition must be there to support nesting other operators
// involving commas (like summations, products, min, other max operators,
// etc.) inside max operator.
!Utils.surrounded(targetTokens.get(k), targetTokens.subList(i+2, last))
&& targetTokens.get(k).getString().equals(",")) {
commaIndices.add(k);
}
}
// Check the pattern of the commas to see if some
// child is missing e.g. max(,b) or max(a,) or
// max(a,,c).
if (commaIndices.get(0) == i + 2) {
// First child is missing, like in max(,b)
throw new InvalidFormatException(
targetTokens.get(i),
allTtokens,
"The first operand of the max operator is missing, max(?,...).");
} else if (Utils.twoConsecutiveValuesExist(commaIndices)) {
// A child is missing somewhere in the middle,
// like in max(a,,b)
throw new InvalidFormatException(
targetTokens.get(i),
allTtokens,
"Some operand of the max operator is missing, max(...,?,...).");
} else if (commaIndices.get(commaIndices.size() - 1) == last - 1) {
// Last child is missing, like in max(a,)
throw new InvalidFormatException(
targetTokens.get(i),
allTtokens,
"The last operand of the max operator is missing, max(...,?).");
} else {
// Reaching this point means that we have the
// correct format i.e. max(a,b,c,...)
// Now let's do the actual parsing! (0_0)
// Create a list of lists of tokens (will
// contain an arbitrary number of lists as max
// can have any number of operands including 1)
List> childrenTokensLists = new ArrayList<>();
// Add a child for each operand
for (int k = -1; k < commaIndices.size(); k++) {
int childFirstTokenIndex, childLastTokenIndex;
if (k == -1) {
childFirstTokenIndex = i + 2;
childLastTokenIndex = commaIndices.get(0) - 1;
} else if (k == commaIndices.size() - 1) {
childFirstTokenIndex = commaIndices.get(commaIndices.size() - 1) + 1;
childLastTokenIndex = last - 1;
} else {
childFirstTokenIndex = commaIndices.get(k) + 1;
childLastTokenIndex = commaIndices.get(k + 1) - 1;
}
List child = new ArrayList<>();
for (int kk = childFirstTokenIndex; kk <= childLastTokenIndex; kk++) {
child.add(targetTokens.get(kk));
}
childrenTokensLists.add(child);
}
// Return
return new NodeRecognizedInfo(
i,
last,
new MaxNode(
parent,
allTtokens,
vm),
childrenTokensLists);
}
}
}
}
}
}
// Return null if the operator was not found
return null;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("Min(");
for (int i = 0; i < getChildrenCount(); i++) {
sb.append(String.format("%s", getChild(i).toString()));
if (i != getChildrenCount() - 1) {
sb.append(", ");
}
}
sb.append(")");
return sb.toString();
}
}
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